This invention relates generally to a system and method for processing a document and in particular to a system and method for generating a list of classifications (a taxonomy) from a plurality of phrases which are extracted from a set of documents.
Various factors have contributed to the storage of vast amounts of textual data information in computer systems and computer databases. The dramatic increase in the storage capacity of computer storage devices, such as hard disks, tape drives and the like and a decrease in the cost of these higher capacity computer hard drives are factors. Other factors include an increase in the transmission speed of computer communications, an increase in the processing speed of personal computers and an expansion of various computer communications networks, such as a bulletin board or the Internet. People therefore currently have access to the large amounts of textual data stored in these databases. However, although the current technology facilitates the storage of and the access to this textual data, there are new problems that have been created by the vast amount of textual data that is now available.
In particular, a person trying to access the textual data in these computer databases needs a system for analyzing and processing the data in order to retrieve the desired information quickly and efficiently without retrieving extraneous information. In addition, the person trying to access the information needs an efficient system for condensing each large document into a plurality of phrases (one or more words) which characterize the document so that the person can browse the phrases and understand the document without actually viewing the entire document. It is also desirable to be able to automatically generate a classification system based on the extracted phrases stored in the computer database so that a person may use the classification system to browse through the database and focus in on the most relevant documents or pieces of textual data in the computer database. The classification system may be known as a taxonomy which consists of one or more subject matter headings with sub-headings reflecting the phrases extracted from the documents in the database.
To generate a typical subject matter classification system, a person must manually generate a classification system into which the one or more pieces of textual data in the database may then be manually or automatically classified. Thus, the typical classification system is manually generated and does not use the extracted phrases from the documents in the database to create the classification system. Therefore, the typical classifications are generally very broad reflecting the inability to more accurately classify the documents since the exact contents of the documents are not known. Thus, the typical classification may permit the user to select only a broad category which probably then contains too many documents to easily review. In addition, for each different database, a new classification system must be manually generated which is slow and time consuming.
Thus, it is desirable to provide a taxonomy generation system and method which solves the above problems and limitations with conventional classification systems and it is to this end that the present invention is directed.
A system and method for generating a taxonomy in accordance with the invention is provided in which the phrases extracted from the plurality of documents or pieces of textual data stored in the database may be used to automatically generate a taxonomy for the database. The generated taxonomy is unique to the particular database (since it is based on the phrases extracted from the database) and permits a searcher in the database to rapidly find documents within the database since the taxonomy has more detail than a typical classification system. Thus, a search through the taxonomy may reduce the number of documents which the user must review. In addition, the taxonomy generation system may automatically generate a taxonomy for any database provided that key phrases from documents within the database are available.
In more detail, a broad topical library is manually generated and used to provide a structure for the taxonomy. The topical library may be of the same broad level of detail as a typical classification system. Next, the phrases extracted from the documents within the database may be clustered and mapped to form maps illustrating the relationships between the phrases within the documents. The phrases in the maps which are connected to the most other phrases in the map, known as leaders, may be used to form the first level of the taxonomy underneath the topical index. Next, phrases which are related to the leaders based on the clustering form the next level of the taxonomy and so on until the taxonomy has been automatically generated. In this manner, the taxonomy generated reflects the actual phrases contained in the database so that it is more accurate than typical classifications.
Thus, in accordance with the invention, a system for generating a taxonomy for a database is provided including a database having a plurality of pieces of text and a plurality of phrases extracted from the pieces of text wherein the phrases are associated with one or more other phrases. A leader phrase from the phrases in the database is identified wherein the leader phrase is associated with a predetermined number of other phrases in the database. A first level of a taxonomy is generated based on the identified leader phrases wherein the leader phrases form a first level of headings in a hierarchical topical outline. A second level of the taxonomy is generated based on phrases in the database associated with the leader phrases wherein the phrases are sub-headings underneath the leader phrases with which they are associated. The generated taxonomy reflects the phrases extracted from the pieces of text in the database so that a user searches through the database using the final taxonomy.